My Davos hero of the day: Yvo De Boer, the UN official who led the Bali climate change talks and who has just chaired a session here with the sort of blunt intelligence that makes the spine tingle. Pick a fight with this man - as the US government tried in Bali - and you'll probably lose.

That's the good news. The bad is that for all his success in Bali, De Boer fears politicians and businesses are going soft on climate change. It's too hard, too expensive - and just not going to be a priority when stockmarkets are crashing.

He wants economic recession to make the world bolder - but doesn't hold out hope that it will happen. He fears a lazy retreat into the short-term hunt for jobs and growth.

De Boer's message was straightforward: it's easy to talk about the medium term - that comfortable moment for politicians that always lies somewhere after the next election - but tougher to do something now. The trouble is climate change science shows serious emissions cuts are needed now.

Today's scrap in Brussels over the EU's promise of 20% cuts in emissions by 2020 shows how hard it will be to get them, he said. EU politicians who boasted of their commitment to change in Bali are now beating each other's brains as they divide up emissions cuts between member states. Britain is not alone in resisting new rules.

This morning's panel mixed energy producers and climate experts. The producers thought technology would come up with the answers. De Boer was having none of it: it's a lazy message, he said - a call to roll over, go back to sleep, nothing's going to happen in the short-term and solutions are going to kick in after that.

There were encouraging signs: plenty of Americans speaking in the debate, lots of talk of India and China. The hall was full of committed people running interesting new projects.

But De Boer did not allow the session to settle into the sort of self-congratulatory complacency that spoil a lot of Davos debate. He was openly sceptical about businesses that talk green for fashion's sake.

Outspoken, challenging and very funny, he is the sort of radical international diplomat that gives multilateralism a good name. If he wasn't Dutch, he'd make a brilliant British prime minister. But even he can't stop climate change on his own.